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<H2><A NAME="SECTION03534000000000000000"></A><A NAME="subsectribi"></A>
<BR>
Tridiagonal and Bidiagonal Matrices
</H2> 

<P>
An unsymmetric<A NAME="19973"></A> 
tridiagonal matrix of order <B><I>n</I></B> is stored in
three one-dimensional arrays, one of length <B><I>n</I></B> containing the
diagonal elements, and two of length <B><I>n</I>-1</B> containing the
subdiagonal and superdiagonal elements in elements <B>1:<I>n</I>-1</B>.

<P>
A symmetric<A NAME="19974"></A> tridiagonal or 
bidiagonal<A NAME="19975"></A>  matrix is stored in
two one-dimensional arrays, one of length <B><I>n</I></B> containing the
diagonal elements, and one of length <B><I>n</I>-1</B> containing the
off-diagonal elements. (EISPACK routines store the off-diagonal
elements in elements <B>2:<I>n</I></B> of a vector of length <B><I>n</I></B>.)

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<ADDRESS>
<I>Susan Blackford</I>
<BR><I>1999-10-01</I>
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